yeah its crazy hard heavy wood if i swing an axe at these rounds will just bounce back
https://www.thegreenyard.com.au/wp-content/uploads/2015/05/Firewood-Properties1.pdf
Density Density is the amount of space a mass of firewood occupies, the denser the wood the less space a given mass takes up, or the greater a particular volume of firewood weighs. For example Sugar Gum is about twice as dense as Radiata Pine, so a cubic metre of Sugar Gum weighs approximately 1070kg, while a cubic metre of Pine weighs only about 512kg
Yes, that's dense-ometer table I use for local species. Believe I might have posted it here once or twice . Eventually I bought the book that has most of the data in it that that table came from - 'Wood in Australia' by Keith Bootle. Worth getting if you're really interested.
Our densest species where I am is southern blue gum at around 900kg/m, and I do burn some, but mostly I prefer peppermint at around 800kg/m (blue gum is more ashy). I also like burning a couple of white gum species like manna gum and candlebark that are around 750kg/m but burn very nicely. Density is not all it's cracked up to be, it's all a compromise. I have some yellow and grey box and it is fine for long burns and overnighters but peppermint will also get through the night. I have some yellow box in the shed that was cut two years ago and is still wet in the middle where peppermint that is cut in October will be ready to burn by May. If I had to travel to get wood, I would take the higher BTU box species but since I don't, peppermint is just fine. It also has very little ash so it gets points that way too.